The US Food and Drug Administration (FDA) has recommended that people buy their dog bones with extra caution.

It’s typical to see warnings about feeding pets the bones leftover from dinners. Cooked bones can splinter easily and damage the digestive tract. But the FDA’s warning extends to commercially available products, including bones that have been processed, flavored, and packaged specifically for dogs.

The agency says it has received reports of pet illnesses related to bone treats, including those that are marketed as “ham bones,” “pork femur bones,” “rib bones,” and “smokey knuckle bones,” according to a statement. In at least 15 cases, dogs have died as a result of bad bones. Others experienced gastrointestinal maladies that led to vomiting, diarrhea, bleeding from the rectum, and blocked digestive tracts. Some of those products may also have been dried from baking or smoking and may contain seasonings and preservatives.

“So if you’re planning to give your dog a stocking full of bone treats this holiday season, you may want to reconsider,” the agency says.

Despite its warning, the FDA has not listed a recall of products from a specific brand on its website. The agency asks that pet owners report problems with dog treats on its product complaint web page.